This will enable the conference bridge hub and now you will need to enable a conference bridge for a user.
Once a number has been assigned, you can select Custom Greeting to enter a short Text to Speech greeting that callers will hear when they connect to to the main Conference hub, before entering the conference room number.
Click Default Conference Settings - This feature allows admins to set up a default conference bridge that is not assigned to a user when assigning a company conference number.
Click the Disabled toggle switch to Enable.
Adjust the Conference settings as needed, and then click Save Changes.